javascript - 有没有更简单的方法来查看对象是否为空？

Question

我当然可以:

var obj = {};
if(Object.keys(obj).length == 0)

但我很好奇是否有办法说:

var obj = {};
if(obj.hasKeys())

甚至:

//already tested, and this doesnt work.  its true because it *is* something.
var obj = {};
if(!obj)

Answer 1

function hasKeys(o) {
    for (var name in o)
        if (o.hasOwnProperty(name))
            return true;
    return false;
}